Due to actualization of environmental problems in recent years, hybrid cars and electric cars have spread. Further, as an air conditioning device which is applicable to such a vehicle, there has been developed an air conditioning device which includes a compressor to compress and discharge a refrigerant, a radiator (a condenser) disposed in a vehicle interior to let the refrigerant radiate heat, a heat absorber (an evaporator) disposed in the vehicle interior to let the refrigerant absorb heat, and an outdoor heat exchanger disposed outside the vehicle interior to let the refrigerant radiate or absorb heat, and which changes and executes respective modes of a heating mode to let the refrigerant discharged from the compressor radiate heat in the radiator and let the refrigerant by which heat has been radiated in this radiator absorb heat in the outdoor heat exchanger, a dehumidifying mode to let the refrigerant discharged from the compressor radiate heat in the radiator and let the refrigerant by which heat has been radiated in the radiator absorb heat in the heat absorber, and a cooling mode to let the refrigerant discharged from the compressor radiate heat in the outdoor heat exchanger and let the refrigerant absorb heat in the heat absorber (e.g., see Patent Document 1).